The invention relates to a refrigerated display case with at least one unit composed of a plurality of wall groups, namely a bottom group, a rear wall group, and a top group, which delimit a refrigerated chamber at the bottom, at the back, and at the top, and with a cooling device that has a refrigerant circuit and whose components at least include a compressor, an evaporator, a condenser, and an electric control unit.
A refrigerated display case of this kind is disclosed, for example, in DE 10 2012 107 713 A1. It is particularly also suited for use in enclosed spaces and features a stable design and a simple variation of the refrigerated display case size, which also makes it possible to refrigerate large quantities of chilled goods.
Refrigeration equipment with higher refrigeration capacities (for example >2 kW) today is mostly still operated with conventional, generally fluorinated, refrigerants, particularly when used in enclosed spaces. One reason for this is the properties of alternative, natural refrigerants such as carbon dioxide or hydrocarbons, which do not allow natural refrigerants to be easily used in existing systems.
For example, because of their ignitability, hydrocarbons such as propane or butane that are used as natural refrigerants are subject to restrictive regulations (e.g. IEC 600335-2-89), which specify that their filling capacities must be restricted to 150 g and below per refrigerant circuit in refrigeration systems of the conventional type. These quantities, though, are insufficient for higher refrigeration capacities. For the necessary quantities above 150 g, the safety requirements become significantly stricter, particularly in enclosed spaces, so that satisfying these requirements entails a considerable expense.
Because of the high expense, in refrigeration equipment for interior spaces, hydrocarbons are usually used, if at all, in refrigerant circuits with filling capacities of up to a maximum of 150 g so that as a rule, only lower performance classes are operated with hydrocarbons (e.g., see Climate Change 17/2014, Dr. Michael Kauffeld, study entitled “Decentralized Plug-In Cooling Appliances” [Decentral steckerfertige Kühlgeräte], German Federal Environmental Agency 2014, Table 3).
Permitting hydrocarbons to also be used in higher performance classes requires the use of relatively expensive systems such as using a plurality of cooling circuits, each individual one of which has a filling capacity of a maximum of 150 g of refrigerant in order to satisfy the safety requirements. In this case, each circuit must be provided with separate components such as condensers or compressors. A system of this kind is disclosed, for example, in the applicant's DE 10 2015 106 620 (which was not yet published as of the application date).
DE 20 2007 015 832 U1 has disclosed a sales display unit with an electrically driven roller shade. It makes no mention of using a natural refrigerant, particularly with a refrigerant quantity of more than 150 g.
Because of the conflicting problems, natural refrigerants, despite good suitability—for example with regard to greenhouse potential, availability, and thermodynamic properties—have not gained widespread acceptance as a refrigerant in higher performance classes. Instead, fluorinated refrigerants are still used, which can be disadvantageous from an environmental standpoint, particularly with regard to their greenhouse potential.